A WRKY transcription factor, TaWRKY42-B, facilitates initiation of leaf senescence by promoting jasmonic acid biosynthesis.

BACKGROUND: Leaf senescence comprises numerous cooperative events, integrates environmental signals with age-dependent developmental cues, and coordinates the multifaceted deterioration and source-to-sink allocation of nutrients. In crops, leaf senescence has long been regarded as an essential developmental stage for productivity and quality, whereas functional characterization of candidate genes involved in the regulation of leaf senescence has, thus far, been limited in wheat. RESULTS: In this study, we analyzed the expression profiles of 97 WRKY transcription factors (TFs) throughout the progression of leaf senescence in wheat and subsequently isolated a potential regulator of leaf senescence, TaWRKY42-B, for further functional investigation. By phenotypic and physiological analyses in TaWRKY42-B-overexpressing Arabidopsis plants and TaWRKY42-B-silenced wheat plants, we confirmed the positive role of TaWRKY42-B in the initiation of developmental and dark-induced leaf senescence. Furthermore, our results revealed that TaWRKY42-B promotes leaf senescence mainly by interacting with a JA biosynthesis gene, AtLOX3, and its ortholog, TaLOX3, which consequently contributes to the accumulation of JA content. In the present study, we also demonstrated that TaWRKY42-B was functionally conserved with AtWRKY53 in the initiation of age-dependent leaf senescence. CONCLUSION: Our results revealed a novel positive regulator of leaf senescence, TaWRKY42-B, which mediates JA-related leaf senescence via activation of JA biosynthesis and has the potential to be a target gene for molecular breeding in wheat.

Effectiveness and the nomogram of small incision lenticule extraction in the correction of myopic anisometropia in adults.

AIM: To evaluate the safety, effectiveness, and predictability of small incision lenticule extraction (SMILE) for the treatment of anisometropia, and to explore the personalized design scheme of SMILE in correcting adult myopia anisometropia based on the nomogram. METHODS: It's a prospective cohort study. Patients with anisometropic myopia of refractive difference ≥ 2.0 diopters (D) who underwent SMILE between September 2020 and March 2021 were enrolled. Clinical features and visual function were assessed preoperatively and at 1wk, 1, 3, and 6mo after the operation. The examination included tests for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, effectiveness index (preoperative CDVA/postoperative UDVA), safety index (postoperative CDVA/preoperative CDVA), nomogram and stereoscopic function. Paired t-test, Wilcoxon signed-rank test and repeated-measures analyses of variance were used for continuous variables, and Pearson Chi-squared test was used for categorical variables. RESULTS: The study involved 45 consecutive patients (average age: 25.0±6.9y; 82 out of 90 eyes underwent SMILE, while 8 eyes were not operated). The average preoperative spherical equivalent (SE) was -4.74±0.22 D. Six months after surgery, the effectiveness index was 1.05±0.12, and the safety index was 1.09±0.11. Seventy eyes (85.4%) exhibited SE correction error within ±0.5 D. The percentage of eyes with Titmus stereoscopic function equal to or less than 200″ significantly increased from 55.6% preoperatively to 88.9% postoperatively (P<0.05). There was statistically significant difference between higher myopia eyes and contralateral eyes in average nomogram value/spherical refraction ratio. CONCLUSION: SMILE is safe, effective and predictable in correcting myopic anisometropia, and it improves stereoscopic visual function of anisometropia patients. The precise and individualized design of the nomogram is a vital element to ensure the balance of both eyes after SMILE.

Cloning and characterization of a non-TIR-NBS-LRR type disease resistance gene analogue from peach.

Cloning of plant disease resistant genes is greatly helpful for disease resistant breeding in plants and the insight of resistance mechanism. However, there are less relevant researches in peach [prunus persica (L.) Batch]. In this study, four NBS-LRR type resistance gene analogs (RGAs) were cloned from genomic DNA of peach. The PNBS2 fragment was also amplified from peach cDNA and the full-length cDNA of PNBS2 (PRPM1, GenBank accession no. AY599223) has been cloned. Sequence analysis indicated that the cDNA of PRPM1 is 3007 bp in length and that the contained ORF encodes for a polypeptide of 917 amino acids. Compared with known NBS-LRR genes, it presented relatively high amino acid sequence identity. The polypeptide has typical structure of non-TIR-NBS-LRR genes, with NB-ARC, LZ, LRR and transmembrane domains. Southern analysis indicated that the PRPM1 gene might be a single copy in peach genome. Northern blot and RT-PCR analysis showed that the expression of PRPM1 was not induced by salicylic acid (SA) in peach young leaves. The isolation of putative resistance genes from peach provided useful bases for studying the structure and function of peach disease-resistance relating genes and disease resistant genetic breeding in peach.

Cloning and characterization of a second form of the rice adenine phosphoribosyl transferase gene (OsAPT2) and its association with TGMS.

A rice gene, OsAPT2, which encodes a putative adenine phosphoribosyl transferase (APRT), was cloned and characterized. Analysis of the cDNA and genomic sequences revealed seven exons and six introns in the OsAPT2. The deduced amino acid sequence of OsAPT2 is highly homologous to those of previously isolated APRTs. RT-PCR analysis indicated that the OsAPT2 transcript in the young panicles of 'Annong S-1' is down-regulated at 29 degrees C, the critical temperature for induction of 'Annong S-1' fertility conversion. Since the panicle is likely the thermo-sensitive organ at the early stages of pollen fertility alternation, the observed heat-induced change in the OsAPT2 expression pattern in young panicles may mediate, at least in part, thermo-sensitive genic male sterility (TGMS) in 'Annong S-1'. An antisense strategy was used to suppress the expression of the OsAPT2 homolog in Arabidopsis, and the obtained homozygous transgenic plants contained lower AMP content, displayed lower pollen germination rates and exhibited some abnormalities in leaf phenotypes and flowering timing. These data suggest that OsAPT2 is likely to be involved in TGMS in the rice line 'Annong S-1'.